In Vietnam so far, the science of happiness has hardly been meticulously studied. We still do not know the concept of happiness and happiness status in real life of people today. What makes them happy or unhappy? Which social group is happier? Which social group is less happy? Why? How to measure happiness? Is the happiness index of Vietnamese people high or low today? What are the cultural characteristics in the concept and enjoyment of happiness of Vietnamese people? The book "The happiness of Vietnamese - Concept, approach & evaluation index" is an attempt to answer the theoretical and practical issues posed in happiness research in Vietnam today. This is a national-level research project, appraised and rated by the National Acceptance Council as "Excellent".